package com.lzk.filter;

import com.alibaba.fastjson.JSON;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import java.io.UnsupportedEncodingException;
import java.util.HashMap;
import java.util.List;

/**
 * 全局过滤器，实现globalfilter，ordered
 */
@Component //将当前类交给spring管理
@Slf4j //lombok提供的注解使用logger打印器
public class LoginCheckFilter implements GlobalFilter, Ordered {


    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        //1.从请求头获取token
        List<String> token = exchange.getRequest().getHeaders().get("token");
        log.info("检查 token={}",token);
        //2.判断是否为受限资源
        String path = exchange.getRequest().getURI().getPath();
        if (!path.endsWith("login") && !path.endsWith("register")){//访问的是受限资源
            //判断是否包含token，如果为空就返回nologin
            if(token == null || token.equals("")){
                //1.响应对象
                ServerHttpResponse response = exchange.getResponse();
                //2.设置返回错误信息
                HashMap<String,Object> data = new HashMap<>();
                //token失效或没有传递，就会报401错误
                data.put("code",401);
                data.put("success",false);
                data.put("message","noLogin");
                DataBuffer buffer = null;
                try {
                    //  4.转换参数，包装buffer对象
                    // 4.1.将数据转换为JSON，再转换为byte数组
                    byte[] bytes = JSON.toJSONString(data).getBytes("utf-8");
                    // 4.2.将byte数组包装到DataBuffer对象中，用于响应给浏览器，构建响应内容
                    buffer = response.bufferFactory().wrap(bytes);

                    // 5.设置完成响应，不会继续执行后面的filter
                    // 5.1.设置响应状态为401
                    response.setStatusCode(HttpStatus.UNAUTHORIZED);
                    // 5.2.设置响应格式
                    response.getHeaders().add("Content-Type","application/json;charset=UTF-8");
                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                }

                // 6.把结果写给客户端
                return response.writeWith(Mono.just(buffer));
            }
            log.info("Token不为空 ，放行");
        }
        // 7.token不为空，继续执行后续filter
        return chain.filter(exchange);
    }

    @Override
    public int getOrder() {
        return 0;
    }
}
